title: In vitro weathering of selected direct esthetic restorative materials.
abstract: Reflectance spectroscopy measurements were used to compare the degree of surface color shift in two classes of visible light-cured resin composites (hybrid and small-particle) and a glass-ionomer restorative. The weathering times investigated were 0, 100, 200, 300, and 400 hours. Environmental factors of heat, ultraviolet light, and moisture were used to affect the surface integrity of the restoratives. The parameter of delta E * ab (overall color difference) of the CIELAB system for measuring small color differences was used. Chroma changes [delta C * ab] and hue differences [delta H * ab] were also determined. Color shifts, chroma changes, and hue differences were observed for all restorative materials evaluated, regardless of the weathering conditions or time intervals imposed. Glass-ionomer cement demonstrated a significantly greater degree of color shift than did the resin composites. There was no significant difference in the amount of overall color change between the two resin composites, although the difference in change in lightness was significant.
authors.affiliation: Department of Operative Dentistry, University of Oklahoma, College of Dentistry, Oklahoma City 73190, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Fruits
authors.forename: M G
authors.initials: MG
authors.lastname: Duncanson
authors.forename: F J
authors.initials: FJ
authors.lastname: Miranda
mesh_terms: D003116:Color; D003188:Composite Resins; D004955:Esthetics, Dental; D005899:Glass Ionomer Cements; D006358:Hot Temperature; D006813:Humidity; D066298:In Vitro Techniques; D008422:Materials Testing / Q000379:methods / Q000706:statistics & numerical data; D013499:Surface Properties; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D003188:Composite Resins; D005899:Glass Ionomer Cements